The present invention relates to a cutting knife for a cutting tool for cutting through adhesive beads on glass panes of vehicles, having an attachment part and a cutting part, the attachment part being provided, on a first end, with a receiving opening for attachment to an oscillating drive adapted to drive the cutting knife in oscillating fashion about an axis that extends perpendicularly to the receiving opening, and tapering toward a second end, with the cutting part and the attachment part extending at a right angle one relative to the other.
Cutting knives that are used in connection with an oscillating drive to cut out glass panes from vehicles are known.
U.S. Pat. No. 4,543,720 to Grunikiewicz et al. describes, for example, a cutting knife with U-shaped cross-section which comprises an attachment part for attachment to an oscillating drive adapted to drive the cutting knife in oscillating fashion about an axis that extends perpendicularly to the attachment opening, and further a cutting part, curved in sickle shape, that is connected with the attachment part through a cross bar.
As the cutting knife is driven by the oscillating drive, it is set into high-frequency rotary oscillation so that the adhesive bead can be cut through by sort of a scythe effect.
The cutting knife is introduced for this purpose from the outside through the gap between the pane and the body flange, the adhesive bead is pierced and/or the cutting knife is introduced through a recess in the adhesive bead, whereafter the oscillating drive is switched on and the adhesive bead is cut through gradually.
A cutting knife with L-shaped cross-section is known from U.S. Pat. No. 4,199,852 to Ayers et al. Contrary to the afore-mentioned cutting knife, that cutting knife instead of being set into rotary oscillation by a rotary oscillating drive, is set into percussion movement by a longitudinally oscillating drive, by which the cutting part, that projects at an angle from the attachment part, is set into oscillating movement perpendicular to the attachment part. A guide roller is provided in this case as support against the glass pane.
It has been found that cutting knives of that kind with L-shaped cross-section are particularly well-suited in certain applications, especially under spatially constrained conditions, for example for detaching a windshield from a motor vehicle. However, the percussion movement presents an especially high risk that the windshield or the vehicle paint may be damaged during that operation.
Therefore, it is a first object of the present invention to provide an improved cutting knife for cutting through adhesive beads on glass panes of vehicles, by means of which glass panes can be cut out even under unfavorable conditions from outside the vehicle.
It is a second object of the invention to provide a cutting knife allowing an untiring working when cutting through an adhesive bead of a vehicle plass pane.
It is a third object of the invention to provide a cutting knife having a long service life.
It is a further object of the invention to provide a cutting knife that reduces the risk of damage to the glass pane and the vehicle paint when cutting through an adhesive bead of a vehicle plass pane.
These and other objects of the invention are achieved by a cutting knife for a cutting tool for cutting through adhesive beads on glass panes of vehicles, having an attachment part and a cutting part, the attachment part being provided, on a first end, with a receiving opening for attachment to an oscillating drive adapted to drive the cutting knife in oscillating fashion about an axis that extends perpendicularly to the receiving opening, and tapering toward a second end, the cutting part and the attachment part being commonly produced from a flat blank and the cutting part projecting from the second end of the attachment part at an angle to the latter, the cutting part having two lateral edges that join each other at the outer end of the cutting part, and at least one of the lateral edges of the cutting part being shaped as a cutting edge with corrugated or serrated edge.
Due to its L-shaped cross-section, the cutting knife according to the present invention permits glass panes to be cut out from outside the vehicle, and this even under geometrically relatively unfavorable conditions. Due to the fact that the oscillating drive sets the cutting part into oscillating movement so that the cutting part moves to and fro in the cutting direction, perpendicularly to its cutting edge, the drive power of the oscillating drive as such is utilized for cutting through the adhesive bead. The corrugation or serration on at least one cutting edge permits improved penetration of the cutting edge into the adhesive bead so that improved cutting efficiency can be achieved with a lesser amount of force applied. At the same time, the risk of breakage is reduced.
According to an advantageous further improvement of the invention, the second lateral edge of the cutting part is configured as a straight cutting edge.
The additional cutting edge, opposite the side of the cutting part with the corrugated or serrated edge, enhances the cutting effect during the forward stroke of the cutting part and simultaneously permits the cutting part to be retracted through an adhesive bead already cut through, if this should become necessary, for example if a new start is desired during the cutting operation.
According to a further embodiment of the invention, both sides of the cutting part are sharpened from both sides so that a bulged cross-section is obtained.
This results in an especially favorable geometry of the two cutting edges and in improved cutting efficiency.
According to a further development of the invention, the attachment part is sharpened in the transition area to the cutting part along at least one lateral edge, although it is preferred to have both sides sharpened, and groove-like recesses are formed that taper off toward the lateral edges.
Such an embodiment results in an especially favorable cutting effect, especially in the transition area between the cutting part and the attachment part, whereby the risk of breakage of the cutting knife is clearly reduced and the cutting operation generally requires the application of less force.
In addition, the fact that the cutting part is sharpened on both sides in the transition area and that groove-like recesses are formed between the cutting part and the flat remaining portion of the attachment part results in improved guidance of the cutting knife during the cutting operation.
According to a further preferred development of the invention, the two cutting edges of the cutting part join each other at the end in the form of a rounded tip.
This facilitates the process of introducing the tool into the adhesive bead at the beginning of the cutting-out operation.
Further, the attachment part and the cutting part preferably extend substantially at a right angle one relative to the other.
It is understood that the features of the invention mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention.